Field testing of irrigation effects on the stability of a cliff edge in loess, North-west China

• Published in: Engineering geology 2011-06, Vol.120 (1), p.10-17
• Main Authors: Xu, L., Dai, F.C., Tham, L.G., Tu, X.B., Min, H., Zhou, Y.F., Wu, C.X., Xu, K.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buildings. Public works; Crack; Exact sciences and technology; Field testing; Geotechnics; Irrigation; Landslide; Loess plateau; Soil mechanics. Rocks mechanics
• ISSN: 0013-7952; 1872-6917
• DOI: 10.1016/j.enggeo.2011.03.007

As it is not uncommon that irrigation has triggered landslides in the Chinese Loess Plateau, a full-scale field testing in a typical cracked plateau in Heifangtai, Gansu Province of China to simulate such phenomenon was conducted. In the study, piezometers were installed to measure the groundwater, and crackmeters as well as inclinometers were used to measure the slope movement. Water was pumped from the nearby source daily to simulate the irrigation process. There was a sharp increase of pore pressure in the undisturbed loess below the crack when the inclinometer registered considerable movement due to the inflow of water via the crack. Such increase in pore pressure also dissipated rapidly. Eventually, the irrigation water daylighted at the major cracks from the face of the plateau leading to local failures. The results show that cracks have significant effects on the flow of the irrigation water into the ground. The rapid rise in the local pore water pressure had reduced the stability of the slope. ► A full-scale field testing in a typical cracked plateau was for first time conducted. ► It was observed that the cracks had penetrated through the plateau edge and extended to slope face, which exerted a control on the inflow and drainage of irrigation water. ► It was concluded that to trigger large scale landslides such as the commonly-occurring loess flow failures at Heifangtai, a rise of groundwater would be necessary.